The invention relates to a head gate of the type comprising at least one tubular structural element and extending in a main plane.
The head gate is a special gate constituting a barrier making it possible to hold farm animals in position, limiting their movements by holding their neck between two parallel vertical bars.
Each structural element comprises a frame in which a substantially rectilinear movable bar is mounted so as to pivot, substantially half-way along its length, about an axis perpendicular to the main plane.
This movable bar can consequently adopt three positions:
an open position providing a space between substantially the top half of the movable bar and the frame, thus enabling the animal to pass its head through the head gate element;
a closed position in which the movable bar is substantially vertical and parallel to an element of the frame, preventing the animal from withdrawing its head from the head gate element;
a release position providing a space between substantially the bottom half of the movable bar and the frame, thus enabling the animal, for example in the event of falling, to withdraw its head from the head gate element through the bottom.
Each head gate element makes it possible to accept one animal, the head gate being formed by the assembly, in the same plane, of as many elements as there are animals.
In the prior art, the head gate elements comprise means of locking the aforementioned movable bar.
By way of example and as described in the patent FR 2 750 292 of the present applicant, FIG. 1 is a partial view of a head gate element showing one of these devices for locking the movable bar.
These locking means usually comprise a hollow control bar 113 mounted on a top part 103 of the frame 101 and a locking fork joint 111 fixed at the top end 110a of the movable bar 110, the locking fork joint 111 coming to straddle the control bar 113.
The control bar 113 is able to move in rotation about its longitudinal axis and has, over its length, projections 121, 122, 123 intended to cooperate with a slide 115 carried by the locking fork joint 111.
The locking fork joint 111 comprises two substantially parallel walls 111a, 111b, extending in the longitudinal direction of the movable bar 110, in which facing oblong holes 130a, 130b are formed, also extending in the longitudinal direction of the movable bar 110.
The slide 115, extending between the walls 111a, 111b of the locking fork joint 111 and being guided in translation in the oblong holes 130a, 130b, cooperates under the effect of its own weight with the projections 121, 122, 123 on the control bar 113 in order to lock the movable bar 110 in its closed position.
The head gate described in the document FR 2 750 292 does not give complete satisfaction.
This is because manufacturing the control bar 113 comprising projections 121, 122, 123 is complex and expensive.
These projections are generally pieces welded onto the control bar 113, which consequently poses problems of positioning the pieces during the welding, and problems of deformation due to the internal stresses created in the material by the welding.
In addition, the document EP-A-1 040 753 describes a head gate comprising a control bar having notches intended to receive a rotating shaft, thus allowing the locking of the movable bar.
However, the control bar described in the document EP-A-1 040 753 is hollow. This certainly simplifies the storage of the basic materials, since a control bar is used having the same characteristicsxe2x80x94and in particular the same diameterxe2x80x94as the longitudinal members.
On the other hand, the use of a hollow control bar presents many drawbacks.
First of all, a hollow bar has less strength than a solid bar. This gives rise to two major difficulties:
firstly, it is necessary to increase the diameter of the bar in order to increase its rigidity, the bar being weakened by the presence of the notches. Thus a new control barxe2x80x94provided with notchesxe2x80x94cannot be easily adapted to head gates already installed, lengthy and expensive changes needing to be made:
secondly, bearings must be placed in line with each of the notches, to absorb the forces. Additional parts are thus necessary, which gives rise to extra cost and less easy installation.
Equally, the production of a notch in a hollow bar gives rise to the formation of sharp surfaces. The result is increased wear on the sliding shaft, and potentially a greater noise when the sliding shaft drops into the notch.
Moreover, the control bar is traditionally produced from an oxidisable material, such as steel. Because of this, an additional galvanisation step is necessary. This operation is extremely expensive and constraining. In addition, it results in not insignificant deformations of the hollow control bar, which may give rise to poor adaptation of the notch to the sliding shaft, thus limiting the locking height. The locking of the movable bar is then not perfectly assured.
The purpose of the invention is to provide a head gate element provided with a device for locking the movable bar which is more secure and less expensive to manufacture.
The invention aims in particular to propose a stronger control bar, with no welds, and affording better locking of the slide.
To this end, the object of the invention is a head gate element comprising:
a substantially flat frame;
a substantially rectilinear movable bar mounted so as to pivot on a shaft fixed to the said frame and substantially perpendicular to the plane, so that the movable bar can be situated in two extreme inclined positions, namely an open position and a release position, as well as in an intermediate so-called closed position in which the movable bar is substantially vertical;
fixed rigidly to one end of the movable bar, a locking fork joint formed by two plates, receiving a transverse slide able to move in translation in the direction of the movable bar;
a control bar able to move in rotation about its longitudinal axis in order to control the possibilities of the movable bar in the aforementioned three positions, this control bar being fixed in translation to the top part of the frame and extending between the two plates of the locking fork joint.
According to a general definition of the invention, the control bar comprises locking means themselves comprising a transverse notch arranged so that the slide can fit therein when the movable bar and the control bar are in the closed position, and the control bar is solid.
The control bar being solid, it is possible to machine a transverse groove in this bar in order to form the said notch. It is thus no longer necessary to carry out welding, the control bar there being more simple and less expensive to manufacture.
The production of a notch in a solid bar does not createxe2x80x94or only slightly createsxe2x80x94sharp surfaces, which considerably reduces wear on the slide.
According to a first embodiment, the control bar can be produced from a strong lightweight metallic material, other than galvanised steel.
The metallic material employed is chosen so that the control bar thus produced is as strong as a hollow bar of the prior art, generally produced from steel, for an unchanged diameter. Because of this, it is possible to associate the control bar according to the invention with an existing head gate without any particular adaptation, and without using any additional part.
The material of the control bar is also lighter than steel, so that the solid bar obtained has a weight comparable with that of the hollow steel bars of the prior art.
The metal used is also chosen so as not to require any galvanisation operation, thus avoiding constraining operations such as in particular handling, the production of orifices on the bar enabling it to be attached and suspended before it is introduced into a galvanisation bath, finishing of the bar (removal of the zinc deposited in excess at the notch, etc).
Consequently the manufacture of the control bar is less lengthy and less expensive.
In addition, since the bar does not undergo any galvanisation, it does not undergo any deformation, and thus ensures perfect locking of the movable bar in the closed position.
The invention makes it possible to obtain a completed metal control bar.
Different metals can be used, for example copper, bronze or a non-oxidisable metal.
The control bar can also be produced from a metal belonging to the group formed by aluminium and alloys thereof.
It also has, with equal external dimensions, substantially the same weight as a hollow steel bar, and comparable strength.
Aluminium has the advantage of having a colour very close to galvanised steel used for the frame of the head gate element. Thus a head gate is obtained whose external appearance is very satisfactory.
In spite of the relatively high price of aluminium, the cost of manufacturing the control bar can be reduced by 10 to 15% by virtue of the invention, in particular because of the elimination of the galvanisation step.
According to a second embodiment, the control bar can comprise a metallic core and a plastic coating.
According to one embodiment, the locking means carried by the control bar also comprise an inclined flat on the control bar so as to form a slope, the bottom of the said slope opening out in the notch and the top of the said slope being oriented towards the open position of the movable bar so that the slide, when the movable bar passes from the open position to the closed position, can slide along the control bar and then along the slope and then fit in the notch.
This slope facilitates the locking of the movable bar by obliging the slide to fit in the notch.
This is because, when the movable bar is actuated and the slide is at the bottom of the slope, the said slide is then already partially engaged in the notch and, coming to abut against the side of the notch opposite to the flat, can only fit in.
The measures described up to now enable the control bar to be manufactured without welding whilst ensuring better locking of the slide.
It is also possible to ensure a precise translation of the slide by preventing unwanted release.
To this end, a head gate element of the type described above is provided, in which the slide is guided in translation by guidance means situated on the internal face of each of the plates of the locking fork joint.
The external faces of the locking fork joint are thus free of any projecting translation device, denying the animals the possibility of lifting the slide.
It will be observed that this arrangement can be used independently of the aforementioned device with notch.
In one embodiment, the guidance means comprise profiles situated on the internal face of each of the plates, the said profiles having their longitudinal axis substantially parallel to the longitudinal axis of the movable bar.
The use of these profiles makes it possible to obtain robust runners at a low production cost.
More precisely, two profiles are fixed to the internal face of each of the plates, the two profiles on the same plate being separated so that the slide can slide along this separation distance.
This type of guidance has sufficient precision for the application in question.
It is however possible to improve it by providing, on the slide, stops arranged so as to slide against the profiles, preventing the slide from coming into contact with the two plates, thus preventing its wedging during its translation movement.
In a particular embodiment, the slide comprises a metallic core and a polymer envelope.
The metallic core enables the slide to attain a weight ensuring correct functioning of the locking means and the polymer envelope makes it possible to obtain a covering with a low coefficient of friction in which it is also possible to form the previously described stops.
In one embodiment, the head gate element also comprises a safety locking device for the closed position of the movable bar, the said device consisting of a removable pin connecting, when it is in place, the locking fork joint and the frame.
The various embodiments can also advantageously encompass safety equipment vis-à-vis the animals.
In particular, the movable bar of the head gate element according to the invention can also comprise, towards its end part opposite to the locking fork joint, means forming a counterweight able to automatically return the movable bar into its open position when it is not being acted on.
This prevents injury to or strangulation of the animals since the head gate can go into the closed position only by means of a deliberate action by the user.
In a variant, a bar connects the said end of the movable bar to the means forming a counterweight so as to prevent the collars of the animals becoming attached to the movable bar.
In another embodiment, these means forming a counterweight extend in a plane parallel to the main plane of the head gate so that they also enable the passage between the bottom part of the movable bar and the frame to be blocked off, on the side which is not provided for the animal to insert his head therein.
Likewise, the movable bar can also comprise, close TO The locking fork joint, means of blocking the passage between the top part of the movable bar and the frame, also on the side which is not provided for the animal to insert its head therein.
By thus blocking the openings not designed for the passage of the head of the animal, risks of jamming are greatly reduced.
In another embodiment, means of controlling the rotation of the control bar are provided.
As a variant, it is also possible to provide an end of rotational travel member, as well as means of locking the control bar for angular position.